At a New York-based IBM laboratory, scientists have created a tiny device that could be a huge advance toward eventual use of light in place of electricity for connection of electronic components IBM researchers have created a photonic crystal waveguide that is a channel of perforated silicon that slows the speed of light down to under 1/300th of its usual speed when light is propagated down the channel. The novel design permits the speed of the light to be varied widely throughout a range through simple application of an electrical voltage to the waveguide. The small device is made from standard semiconductor materials, and the slow light can be closely controlled. The technology has the potential to make possible the construction of highly compact optical communications circuits that are pragmatic for integration into computer systems. IBM's photonic crystal waveguide answers several questions that have been asked over the years in relation to cost of manufacturing, control of the light signal, and the minute size required. The pattern and size of the holes on the photonic crystal waveguide provide the material with a very high refractive index, and heating the waveguide locally with a small electrical current change to refractive index so that the speed of light can be swiftly tuned over a large range with very low applied electric power. The active area of the device is in the microscopic range, and the manufacturing processes used to build the device can be had in just about any semiconductor laboratory.